Method and apparatus for drawing foils into pipes



Nov. 24, 1970 QPAT-ZAK ETAL 3,541,667

METHOD AND APPARATUS FOR DRAWING FOILS INTO PIPES Filed Aug. 23. 1968 United States Patent Office 3,541,667 Patented Nov. 24, 1970 US. Cl. 29429 13 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus of drawing foil liner into a tube, sliding a casing over the tube, attaching the liner to the casing thus forming a liner for the casing. The casing being used as a casting tube for plastic material.

BACKGROUND AND OBJECTS This invention relates to a method and apparatus for lining the inside walls of a casting pipe with a foil, particularly for use in pouring a plastic material into the casting pipe and removing same.

In making rods of plastic material, for example, raw stock for making buttons, the molding for casting pipes have in the past been lined with a silicone material. The plastic has been poured into the lined casting pipe and has been allowed to harden, either completely or partially. This process is very laborious because the silicone lining must very often be renewed or recoated. Furthermore it has been found that the cast rods sometimes are very difiicult to remove from the molding or casting pipes. Therefore, hinged pipes have been proposed in the past; however, they are comparatively difiicult to utilize.

The instant invention is intended to provided a method and apparatus for preparing casting pipes which will facilitate the easy extraction or removal of the cast rods, even when these rods are still rubbery or soft. The invention will also prevent the casting material from adhering to the pipe wall.

In solving the prior art disadvantages, the solution has been found essentially in the fact that a foil with an original width being greaterthan the outside circumference of the casting pipe is drawn into an inner tube or casing. This is done by guide apertures which are arc-shaped so as to curve the flat foil material into a circular shape to conform with the inner tube. The outside diameter of the inner tube is smaller than the inside diameter of the casting pipe. The casting pipe is moved over the inner tube and the free end of the foil is attached to the free of the casting pipe. This pipe is then drawn over and oil the inner tube. As a result, the foil is moved from the inner tube to the casting pipe. Finally, the foil is separated from the pipe and the inner tube. In this way an inside lining for the casting pipe is obtained and this lining will closely hug the inside Wall of the casting pipe and Will be freed from any wrinkles. The finished cast rods are easily extracted from the casting pipe by pulling on the foil. Therefore, the traction forces will attempt to press the material radially inward. This will result in the fact that the cast rod will be more easily removed from the casting pipe.

The foil is preferably unwound from a supply roller, thei slupply on the roller already being cut to the correct wi t The free end of the foil is preferably attached at the free end of the casting pipe with an elastic stopper. As a result, the foil can be made to hug the inside of the casting pipe Without any wrinkles.

It has been found that it is particularly advantageous when using a polyester foil that a thickness 20-50 microns be used, or if a polyethylene foil is used, the preferable thickness is 50-150 microns.

SUMMARY OF THE INVENTION The method and device for carrying out the instant invention includes a fixed inner tube having at one end a series of guide slots to axially move the foil material from the roller circumferentially into the interior of the inner tube. A casting pipe support is provided at the other end of the inner tube which is moveably mounted in an axial direction with regard to the inner tube and is intended to surround the inner tube in one position and be moved completely away from the inner tube in another position. An elastic stopper is used to attach the foil at its free end to one end of the casting pipe.

A cutting device for cutting the foil may be further provided at a point just past where the foil leaves the end of the inner tube.

The elastic stopper may be designed in such a form that it is hollow with a bulge protruding radially inward. This bulge and hollow space in the stopper cooperate with a rigid, nonelastic plug. A stopper of this design is easily inserted and removed and will not shift or Wrinkle the foil.

BRIEF DESCRIPTION OF THE DRAWINGS The invention and objects thereof will be best understood and more apparent from the following drawings wherein:

FIG. 1 is a side elevation view of a device according to the invention;

FIG. 2 is a top plan view of the device according to FIG. 1;

FIG. 3 is a cross-sectional view of the stopper inserted within a casting pipe.

DETAILED DESCRIPTION OF THE INVENTION The device according to the invention as illustrated in FIGS. 1 and 2 includes a supporting frame 8 on which an inner tube 4 is fixably secured. At the right end of the tube is seen in FIGS. 1 and 2 there are a plurality of axially aligned foil guide slits, 3a, 3b and 30. These are arranged longitudinally so as to be moveable on a guide line. In the lower portion of the frame 8 is located a supply roll 1 which includes foil material 11 which is conveyed from an axial support 12 by means of guide rollers 2 in a form of a flat sheet into the axis of inner tube 4. The foil guides 3a, 3b, and 3c are arcuate in shape and continually increase the curvature of the foil as it moves from rollers 2 into the inlet at 10. Therefore, the foil 11 will begin as a fiat sheet and become continually more curved until it is in a circular crosssectional shape as it enters the inner tube 4.

For best guidance of foil 11 in the area of the foil guides, the guides may be in the form of cutouts or slots through which the foil is guided. In order to further improve the guiding of the foil, a spike-like member may be located in the vicinity of the inlet 10 of inner tube 4. This will prevent the foil from bulging at the opening and the inside of the inner tube.

The inner tube 4 is attached to the frame 8 only at the end adjacent inlet opening 10 by a support at that point. The other end is free from any support means so that a casting pipe as seen at 5 can be pulled or pushed over the end as indicated by the dash lines at 5a. In front of the free end of the inner tube 4 is a bearing block 6 on which is placed the casting pipe 5 and over which the casting pipe moves axially with respect to the inner tube 4.

As will be discussed below, a pipe lock as seen in FIG. 3 includes a rubber or other elastic type stopper 13 which has a hollow portion 130:. This may be easily inserted into the casting pipe 5 withthe foil 11 therein. The hollow portion of the elastic stopper 13 includes a bulged portion 16 which projects radially inward. A nonelastic plug 15 having a recess which is complimentary with the radially projecting portions 16 may be inserted therein as will be discussed below.

OPERATION The method of operating the device begins by suspending a supply roll 1 having the foil 11 thereon. This is suspended axially on the roller indicated at 12 which in turn is mounted on the frame 8 in the lower portion. The foil is then guided over the lower and upper guide rollers 2. It is then gradually pushed through the slots in the guide means 3c, 3b and 3a and finally into the entrance opening at 10 of the inner tube 4. The foil guide slots provide the initially flat foil strip 11 with an increasingly curved shape until it is circular in form. The longitunial edges of the foil will overlap upon entry into the inner tube 4. The foil is then pushed forward in any known manner until the end of the foil strip extends outwardly of the free end of the inner tube 4. The device is now ready for use with the casting pipe.

The casting pipe 5 is placed on the bearing block 6 and then axially moved over the inner tube 4. The bearing block 6 is so designed that a casting having been placed upon it will be in line axially with the inner tube 4 so that it can be easily moved over the latter.

As seen in FIG. 1, the foil 11 protrudes somewhat from the free end of the inner tube 4. The casting pipe is now pushed over the inner tube until the end of the foil terminates with the far end of the casting pipe. This position of the casting pipe is illustrated in FIG. 1 in dash lines and designated as 511.

The pipe lock as illustrated in FIG. 3 is now inserted in the casting pipe. The pipe lock which includes the rubber or elastic stopper member 13 having the hollow portion 13a therein is inserted into the end 14 of the casting pipe 5. As indicated above, the plug 15 having a complementary recess with the bulge 16 is now inserted. By moving the plug axially, the bulge is pressed 0ut ward radially and the foil 11, which is located between the stopper and the casting pipe, is forced tightly against the pipe without shifting or moving the foil and without wrinkling it. The casting block is then returned to its left-hand starting position from 5a to the location as seen in FIGS. 1 and 2. Since the foil is firmly clamped in place in the end 14 of the casting pipe, the entire foil strip is moved along therewith. Therefore, the foil will closely hug the inside wall of the casting pipe 5 upon coming oif of the free end of the inner tube 4. After the enttire length of the casting pipe 5 has been drawn oif of the inner tube '4, the foil 11 is cut by means of a cutting device 7 or by means of some other suitable device so that the inner tube 4 will once again be ready for the next operation. The casting pipe 5 is now lined along its entire length with the foil and it is closed with a stopper at one end 14 so that it can be immediately filled or lined with a plastic or similar substance.

After partial hardening of the plastic, the stopper 13 can be removed and the plastic rod thus formed can be easily removed from the casting pipe 5. The casting pipe need not be cleaned for the next operation; instead, it can immediately be pushed over the inner tube 4 whereby the entire operation is then started again.

It will be apparent that the method and device described above offers the advantage that the casting pipe can be prepared for casting operations comparatively 4 faster than can be done with the prior art methods and devices. Furthermore, the rods which have been cast using this device yield a very smooth surface so that in many cases it will not be necessary to do any further processing.

We claim:

1. A method of preparing casting pipe comprising:

(a) feeding a fiat foil material from a supply means through arcuate shaping means,

(b) shaping said flat foil into a substantially circular form,

(c) forcing said circular formed foil into and through an inner tube,

(d) sliding a casting pipe over said inner tube, and

(e) securing said circular formed foil to said casting 2. A method as defined in claim 1 including sliding said casting pipe off said inner tube and severing the unsecured end of said foil between said casting pipe and said inner tube.

3. A method as defined in claim 1 including overlapping the edges of said circular formed foil in said inner tube.

4. A method as defined in claim 1 wherein said shaping step is accomplished by forcing said fiat foil through arcuate slots and increasingly curving said flat foil until it is substantially circular.

5. A method as defined in claim 1 wherein said securing step includes placing an elastic stopper means in said casting pipe, said circular formed foil being between said stopper and the inside of said casting pipe.

6. Apparatus for preparing casting pipes comprising:

(a) a support frame,

(b) an inner tube secured to said frame,

(c) a casting pipe slidably moveable over said inner tube in an axial direction,

((1) lgneans for supplying foil material into said inner tu e,

(e) means for shaping said material into the shape of said inner tube.

7. Apparatus according to claim 6 wherein said shaping means includes a plurality of members having arcuate slots therein.

8. Apparatus according to claim 6 wherein said foil is a polyester having a thickness of approximately 2050 microns.

9. Apparatus according to claim 6 wherein said foil is a polyethylene having a thickness of approximately 50-150 microns.

10. Apparatus according to claim 6 including means for securing said foil to said casting pipe.

11.Apparatus according to claim 10 wherein said securing means includes an elastic stopper.

12. Apparatus according to claim 11 wherein said stopper has a hollow interior, a bulge projecting radially into said interior, and plug means for exerting a pressure on said projecting bulge.

13. Apparatus according to claim 6 including cutting means for said foil, said cutting means being located at the outlet end of said inner tube.

References Cited UNITED STATES PATENTS 3,069,763 12/ 1962 Reynolds 29-429 3,293,737 12/1966 Falkenau et al. 29-423 THOMAS H. EAGER, Primary Examiner US. Cl. X.R. 29-200 

